These are just a few of the physical and emotional responses soldiers reported upon their first combat experience.

Sure, there are hundreds of books, movies, and other multimedia that can give a sense of what it's like to be shot at, bombed, or rocketed. Then there are the stories a soldier or Marine may be told by a senior leader on "what it's really like."

But there's also some hard data, thanks to a recent study carried out by Aaron Bazin at West Point's Modern War Institute. Bazin polled 304 military veterans, spanning from Vietnam to present day, on their experience in a "combat situation," which he defined as "any event where the person’s life was put at risk in direct contact with an enemy force (e.g., shooting, bombing, indirect fire, etc.)."

Not surprisingly, the most-reported physical response was an increase in heart rate. Also reported were rapid breathing, muscle tension, and tunnel vision. These changes in the body are well documented as part of the so-called "fight or flight response."

I found the questions regarding emotional response much more enlightening. While anticipation was the one emotion most experienced by soldiers before combat, upwards of 30% reported fear before and during combat, blowing apart a macho myth that you're not supposed to ever be scared during battle.

An overwhelming number of veterans said they "didn't think" and just acted during combat — giving a positive nod to their training beforehand. Indeed, the majority of respondents said their training prepared them very well or somewhat well for combat duty (91.5%).

"Simply put, once a service member knows battle first hand and survives, he or she will likely never be the same again," Bazin writes. "The fact remains, the more new service members can learn from the experiences of those that have gone before them, the better they can prepare themselves for what may lie ahead."